1. Field of the Invention
This invention relates to novel laundry detergent compositions having a high water-soluble alkaline carbonate builder content, the use of which results in improved cleaning performance.
2. Background Information Including Description of Related Art
Laundry detergent compositions comprising a water-soluble alkaline carbonate are well-known in the art. For example, it is conventional to use such a carbonate as a builder in detergent compositions which supplement and enhance the cleaning effect of an active surfactant present in the composition. Such builders improve the cleaning power of the detergent composition, for instance, by the sequestration or precipitation of hardness causing metal ions such as calcium, peptization of soil agglomerates, reduction of the critical micelle concentration, and neutralization of acid soil, as well as by enhancing various properties of the active detergent, such as its stabilization of solid soil suspensions, solubilization of water-insoluble materials, emusigication of soil particles, and foaming and sudsing characteristics. Other mechanisms by which builders improve the cleaning power of detergent composition are probably present but are less well understood. Builders are important not only for their effect in improving the cleaning ability of active surfactants in detergent compositions, but also because they allow for a reduction in the amount of the surfactant used in the composition, the surfactant being generally much more costly than the builder.
While laundry detergents containing a relatively large amount of carbonate builder are generally quite satisfactory in their cleaning ability, there exist situations wherein even better performance in the removal of certain types of soils comprising oily particulates and fatty deposits such as sebum, would be advantageous. Thus, any change in available carbonate built laundry detergent compositions which improves their ability to remove such soils is highly desirable.
Possibly relevant to the invention claimed herein are U.S. Pat. No. 4,265,790, issued May 5, 1981 to Winston et al.; U.S. Pat. No. 4,464,292, issued Aug. 7, 1984 to Lengyel; and U.S. Pat. No. 5,376,300 issued Dec. 27, 1994 to Bolkan et al., each of which discloses detergent compositions comprising an ethoxylated long chain alcohol and a sulfate of an ethoxylated long chain alcohol as a combination of nonionic and anionic surfactants, and over 70 wt. % of anhydrous sodium carbonate (soda ash) as a detergent builder.